The 500 series indicates that something went wrong while processing the request on the server side. These may possibly arise when exceptions are not handled properly, when the server ends up in a run-time exception, or with any other errors, such as out of memory. This indicates that the request cannot be fulfilled.

The 500 series status code informs us that there is something wrong with the execution of the action performed in the given resource:

• 500 Internal Server Error: This status code indicates that the requested action has not been processed successfully by the server. This occurs when the server encounters an error while processing the request and the server returns the 500 status code.
• 503 Service Unavailable: This status code indicates that the server is not available to process the request or when it is down.
• 504 Gateway Timeout: This status code indicates that the request is sent to the server but the response was not received on time.